Young broiler type chickens that are grown commercially for market have a high percentage of both solid and liquid fat in their carcasses at time of evisceration at the slaughter plant. This creates a problem of substantial proportions when the poultry carcasses are chilled in a poultry chiller at the slaughter plant in an ice-water bath that is usually air-agitated for approximately one hour to reduce the carcass temperature to below 40.degree. F. as required by regulations of the United States Department of Agriculture (USDA). The problem arises from the fact that substantial quantities of oil or fat are washed off of the carcass in the chilling process and are emulsified in the ice water by the air agitation to form a scum or layer of fat floating on the surface of the chilled water. The scum is quite unsightly and tends to coat the birds with an undesirable greasy film that reduces the appearance and quality of the finished product.
The water use in an elongated chiller tank or trough of a poultry chiller is normally chilled to approximately 32.5.degree. F. by means of a separate remote shell and tube heat exchanger following which it is pumped into the bird outlet end of the chiller tank at the rate of approximately 400 to 600 gallons per minute. The water is continuously removed from the chiller tank and returned to the heat exchanges and cooled to 32.5.degree. F. and pumped back into the chiller at the bird-outlet end of the chiller tank. The chilled water flows upstream toward the bird inlet end of the chiller against the movement of the carcasses toward the bird outlet end of the chiller, which movement of the carcasses is effected by conventional mechanical means, such as an auger or movable paddle members. The temperature of the chilled water increases to approximately 38.degree. F. to 42.degree. F. as it travels from the bird outlet end to the bird inlet end of the chiller.
The pump suction connection is provided in the bottom wall of a pump suction chamber attached to the outside of the bird inlet end of the chiller and which is designed so as not to interfere with the normal travel of the carcasses through the chiller. The pump suction chamber communicates with the main body of the chiller tank or trough through a series of closely spaced rods or a screen through which the water can flow into the pump suction chamber. However, the rods or screen prevent the carcasses from following the water into the pump suction chamber.
Unfortunately, the fat and "scum" that is accumulating on the surface of the water follows the water flow in the chiller and if the fat is not collected and disposed of, it soon becomes a two to three inch thick "foamy scum" that backs up from the pump suction chamber and eventually covers a major portion of the water surface in the chiller tank. A more-or-less continuous and costly manual skimming of the foamy scum accumulation that gathers in the pump suction chamber is consequently required for presently known chillers. The scum skimming operation is made difficult by the relatively small size of the pump suction chamber which is approximately 28" L.times.18" W.times.48" D and by the fact that the water level can vary vertically from 6" to 12" below the top edge of the chiller tank. Further difficulty arises from the fact that since the unit handles edible food products, any solution to the scum removal problem must satisfy all USDA requirements for sanitation and cleanability.
Therefore, it is a primary object of the present invention to provide a new and improved method and apparatus for removing floating fat from the surface of a body of liquid.
A more specific object of the present invention is to provide a new and improved apparatus and method for removing floating fat from the surface of chiller water in a poultry chiller tank.
Another object of the present inventions is the provision of power driven fat skimmer apparatus that can be attached to a poultry chiller without need for any modification of the poultry chiller.
A further object of the present invention is the provision of fat skimming apparatus that can be easily adjusted to optionally operate for removal of fat from the surface of a body of water for various flow conditions and water levels in the chiller tank.